Trampoline

ABSTRACT

A trampoline having a mat spaced from the floor comprises a circular frame, the mat being resiliently attached to said frame centrally thereof. This frame is built up from sections each forming a rigid unit together with a socket for connecting an adjacent section thereto and a leg for supporting the frame, straight struts interconnecting the legs at the lower ends thereof to form a polygonal lower frame.

United States Patent 1 Eriksson 1 Oct. 23, 1973 I [73] Assignee: Ingenjorsfirman Idema,Sibbhult, V 7

Sweden [22] Filed: Mar. 3, 1971 [21] Appl. No.: 120,537

[30] Foreign Application Priority Data 2,991,841 7/1961 Sampson et al 182/139 2,977,118 3/1961 2,930,430 3/1960 Bloom 272/60 UX FOREIGN PATENTS OR APPLICATIONS 1,166,065 3/1964 Germany 272/65 919,990 2/1963 Great Britain 272/65 Mar. 6, 1970 Sweden 3050 Primary ExaminerRichard C. Pinkham Assistant Examiner-Richard J. Apley [52] US. Cl. 27 2/65, 182/139 A r M lcolm W, Fraser [51] Int. Cl. A63b 5/00 [58] Field of Search 272/60, 65;

182/136-140; 52/648, 654 [57] ABSTRACT A trampoline having a mat spaced from the floor com- [56] References Cited prises a circular frame, the mat being resiliently at- UNITED STATES PATENTS tached to said frame centrally thereof. This frame is built up from sections each forming a rigid unit tog fi gz g gether with a socket for connecting an adjacent sec- 1,521:422 12 1924 Boydm: 52/654 and a leg suppmting the frame 1,960,328 5/1934 Breines.. 52/643 X Straight struts interconnecting the legs at the lower 2,083,051 6/1937 Chapas 52/648 X ends thereof to form a polygonal lower frame. 2,571,753 10/1951 Pennington.... 52/648 3,356,366 12/1967 Barthel 272/65 1 Clam, 8 Drawllla Figures 3,031,688 5/1962 Southwood 182/139 X 3,137,371 6/1964 Nye 272/60 UX L ii 1 1 Patented Oct. 23, 1973 3,767,192

' 3 Sheets-Sheet l Patented Oct. 23, 1973 3 Sheets-Sheet 2 Patented Oct. 23, 1973 3 Sheets-Sheet TRAMPOLINE This invention relates to play and gymnastics appliances and particularly to a trampoline of the type comprising a mat attached resiliently to a horizontal frame spaced from the floor, which is used by acrobates, gymnasts and children as a spring board in tumbling and playing. I

In a trampoline of this type now commonly used there is provided a sheet of canvas, coated or rubberized fabric, plastic cloth or the like, which is resiliently suspended in a rectangular frame. Due to the fact that the frame is rectangular resilient members connecting the sheet with the frame are non-uniformly loaded to a substantial degree the load being dependent on where the user of the trampoline hits the sheet and also on the resilience of the frame.

According to the invention it has been found that the elastic force exerted by the resilient members will be much more uniformly distributed if a circular frame is used due to the fact that all the resilient members will be substantially equally loaded and also due to the fact that the resilience of the frame will be negligable since it is counteracted by the forces exerted by the opposed resilient members. Furthermore, it has been found that a greater useful trampoline surface will be obtained at the same consumption of material for the sheet when this sheet is suspended in a circular frame than if it is suspended in a rectangular frame. In consideration of weight this is extremely advantageous if the frame is to be dismantled and moved from one place to another as is usual.

Accordingly, the invention provides a trampoline comprising a sectional upper circular frame, a leg on each frame section forming a rigid unit therewith, a socket on each frame section for connection with an end portion of an adjacent frame section, a sheet, resilient elements connectinga marginal portion of said sheet with said upper frame for mounting said sheet in said frame, and straight struts interconnecting said legs at the lower ends thereof and forming a polygonal lower frame taking up compression strains during the use of the trampoline.

The invention now will be described in greater detail reference being made to the accompanying drawings.

FIG. 1 is a side view of the stand of the trampoline according to the invention;

FIG. 2 is a plan view of the trampoline;

FIG. 3 is an enlarged fragmentary plan view of part of the stand at the region A in FIG. 1;

FIG. 4 is an enlarged fragmentary sectional view of one of the legs and the base plate thereof taken on line F-F in FIG. 3;

FIG. 5 is an enlarged fragmentary vertical sectional view of a frame section at a joint taken on line 8-8 in FIG. 3 the rigid connection between the several elements being clearly shown;

FIG. 6 is an enlarged vertical sectional fragmentary I view of a lock clamp and connecting parts of the mar- 'ginal portion of the sheet and of a rubber element;

FIG. 7 is a plan view of the lock clamp and adjacent parts of the marginal portion of the sheet and the rubber element shown in FIG. 6; and

FIG. 8 is a cross-sectional view of the heavier end portion of the lock clamp, provided with recesses for the rubber element, taken on line D-D in FIG. 7.

As will be seen in FIGS. 1 and 2 the trampoline according to the invention comprises a stand including a circular supporting frame 1 having legs 2 provided with base plates 3 and interconnected by means of straight struts 4 forming a hexagonal lower frame of the stand. The mat comprises a sheet 5 of canvas, coated or rubberized fabric, plastic cloth or the like, which is suspended centrally in frame l by means of resilient members each consisting of an elongated rubber element such as shown at 6a, 6b and 6c, such rubber elements being mounted between the sheet and the supporting frame by means of lock clamps 7.

FIGS. 6, 7 and 8 show that each clamp has a longitudinal sectional form substantially as the letter C with two opposite hook like end portions, the clamp tapering from one end to the other. The thin end portion engages openings in the marginal portion of the sheet, such openings being provided with strengthening eyelets, the heavy end portions being embraced by one end of a rubber element 6. In order to reduce the wear between that part of the rubber element which engages the heavy end portion of the clamp, said part of the rubber element is preferably thicker in cross section as shown than the rest of such element. Furthermore, the

heavy end portion of clamp 7 is provided with horizontal side recesses to receive therein the end of the rubber element as will be seen in FIG. .8. i

The edge portion of the sheet received by one end portion of the clamp extends so far into the clamp that it is close to the rubber element embracing the other end portion of the clamp, in order to prevent the marginal portion of the sheet and the rubber element to disengage the clamp unintentionally.

Frame 1 is made up of sections such as la and 1b in FIG. 3 which are detachably interconnected by means of a socket l0 fixedly connected with one of the adjacent ends of two sections. A leg 2 is rigidly connected to each section. Socket 10 may comprise a plastic material socket having pressure fit on the associated section.

The interconnection of legs 2 by means of struts 4 is important since the supporting frame and the legs thereby form a sturdy integral unit. The struts may be detachably connected with the base plates by means of screw connections III as shown in FIGS. 3 and 4.

If a person weighing for instance pounds tumbles by using the trampoline described the tensile force in each rubber element is calculated to be about 32 pounds and the elongation about 70 percent when the person hits the sheet. The total deflection of the sheet in the center thereof will be less than 2 inches in the circumstances described. The strain in the connection between the supporting frame and the legs being substantial the legs tend to fold inwardly. However, this is effectively prevented by the rigid connection between each frame section and the associated leg and by the fact that the lower ends of the legs are each inserted in a base plate 3 and that such base plates are mutually braced by means of struts 4 forming the polygonal lower frame taking up compressive strains.

The invention is not limited to the embodiment shown and described since modifications of details thereof may be made without departing from the spirit of the invention as defined in the claims.

What is claimed is:

l. A trampoline comprising a sectional upper circular frame, a leg on each frame section forming a rigid unit therewith, a socket on each frame section for connection with an end portion of an adjacent frame section,

cesses for locating the rubber element associated therewith, the part of said rubber element engaging the lock clamp being close to the marginal portion of said sheet and said marginal portion and said rubber element thereby being prevented unintentionally to disengage said lock clamp, and straight struts interconnecting said legs at the lower ends thereof and forming a polygonal lower frame taking up compression strains during the use of the trampoline. 

1. A trampoline comprising a sectional upper circular frame, a leg on each frame section forming a rigid unit therewith, a socket on each frame section for connection with an end portion of an adjacent frame section, a sheet, resilient connecting means securing a marginal portion of said sheet with said upper frame for mounting said sheet in said frame, said connecting means comprising an elongated rubber element mounted between said upper frame and a lock clamp engaging the marginal portion of the sheet, and in which said lock clamp has a longitudinal section formed as the letter C, one end portion of which is thinner than the other end portion and engaging said sheet, and in which said other end portion of said lock clamp provides side recesses for locating the rubber element associated therewith, the part of said rubber element engaging the lock clamp being close to the marginal portion of said sheet and said marginal portion and said rubber element thereby being prevented unintentionally to disengage said lock clamp, and straight struts interconnecting said legs at the lower ends thereof and forming a polygonal lower frame taking up compression strains during the use of the trampoline. 